here's a run down of of my thoughts...

1. your bulbs are they LED? if so there's your problem, they draw much less current than normal bulbs. either put in the norma bulbs or get a load resistor to make the blinker "see" the right load.

2. are both the front and rear bulbs blinking on each side? if not then replace the burnt out bulbs.

3. have you done anything or changed anything to make this happen?

4. does your hazard switch work? the normal blinkers go through your hazard switch.

5. replace your blinker relay with an OEM one. If you go to an aftermarket parts store make sure to get the one for a honda civic, they are different than the generic ones.

6. if it still does it there is a wiring issue somewhere.